Systems and methods for closed loop solvent extraction and purification

ABSTRACT

Provided herein are systems and methods for the facile extraction and purification of oils from plant material, including cannabis and hemp. The systems and methods herein are versatile, and may utilize a wide range of solvents to extract oils from a variety of plant-based material. Further, the provided systems and methods are closed loop, reducing the loss solvent and decreasing the risk of safety concerns such as human exposure to solvent chemicals or explosion of volatiles. In some embodiments, the systems and methods remove impurities from the extracted oils, for example waxes or other precipitates, and provide a higher purity and higher quality extract.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.15/163,618, filed May 24, 2016, which claims the benefit of and priorityto U.S. Provisional Application No. 62/187,798, filed Jul. 1, 2015,which is hereby incorporated by reference in its entirety to the extentnot inconsistent with the disclosure herein.

BACKGROUND OF INVENTION

This invention is in the field of extraction and refining of essentialoils from biological material. The invention relates generally to theclosed loop extraction of oils from plant matter. The invention alsogenerally relates to the purification of extracted oil to removeunwanted compounds extracted concurrently with the oil, such as waxes.

Oils derived from plant matter are desirable in a wide variety ofindustries and applications. For example, the fragrance and perfumeindustries require a variety of essential oils for fragrance compounds.The food industry also extracts specific taste-affecting compounds andflavors from plants. Extraction has been utilized to extract a widearray of compounds such as medicinals, lipids, carotenes, alkaloids,tocopherols, and tocotrienols. More recently with the decriminalizationof medical cannabis, and in some states legalization of recreationalcannabis, extraction of pharmacologically active compounds frommarijuana, such as tetrahydrocannabinol (THC) and cannabidiol (CBD),have received increased attention.

Currently, the most common methods for the extraction of oils from plantmaterials are solvent extraction and supercritical fluid extraction(SFE). SFE uses supercritical fluids to selectively remove extracts fromsolids, semisolids and liquids. Both solvent extraction and SFE havebeen developed using a variety of solvents, for example, carbon dioxide,propane, butane, ethane, ethylene, propane, propylene, cyclohexane,isopropanol, benzene, toluene, p-xylene, chlorotrifluoromethane,trichlorofluoromethane, ammonia and water. Each specific solvent hascertain advantages and disadvantages and solvents tend to be selectedbased on the equipment being used, chemistry of the extract and plantmaterial, safety, government regulations, and cost.

Current methods of SFE and solvent extraction both have disadvantages inthe cost or complexity of the equipment required. For example, SFE caninvolve heating the solvent to tight-tolerance temperatures andpressuring to high pressures, which is both costly and a safety concern.While solvent extraction is often performed at lower temperatures andpressures, current methods often risk exposure to the solvent materialwhich can be toxic, explosive or carcinogenic. Additionally, solvent maybe lost between non-interconnected components. Current solventextraction methods also have selectivity problems, as they often extractadditional compounds, such as waxes, which are undesirable in the oilproduct.

As can be seen by the foregoing, there remains a need in the art forclosed loop solvent extraction methods and systems for the extraction ofoils from plant material which provide reduced costs, higher safety andincreased purification and removal of waxes from the extracted oil.

SUMMARY OF THE INVENTION

Provided herein are systems and methods for the facile extraction andpurification of oils from plant material, including hemp or cannabis.The systems and methods herein are versatile, and may utilize a widerange of solvents to extract oils from a variety of plant-basedmaterial. Further, the provided systems and methods are closed loop,reducing the loss of solvent and decreasing the risk of safety concernssuch as human exposure to solvent chemicals or explosion of volatiles.In some embodiments, the systems and methods remove impurities from theextracted oils, for example, waxes or other precipitates, and provide ahigher purity and higher quality extract.

In an aspect, provided is a method for closed loop extraction of oilsfrom plant material, the method comprising the steps of: (i) providingan extraction system comprising: (a) a solvent vessel for containing asolvent; (b) an extraction vessel removably connected to the solventvessel; and (c) a collection vessel removably connected to theextraction vessel and removably connected to the solvent vessel, whereinthe collection vessel is positioned gravitationally lower than theextraction vessel; (ii) filling the solvent vessel with the solvent;(iii) heating the solvent vessel, thereby flowing the solvent from thesolvent vessel into the extraction vessel, wherein the solvent extractsoils from the plant material; (iv) heating the extraction vessel; (v)cooling the collection vessel to a temperature lower than a temperatureof the solvent vessel, thereby flowing the solvent and oils into thecollection vessel; and (vii) heating the collection vessel to evaporatethe solvent thereby returning at least a portion of the solvent to thesolvent vessel and leaving at least a portion of the oils in thecollection vessel.

In embodiments, for example, the solvent flows through the extractionsystem by a differential pressure between the solvent vessel, theextraction vessel and the collection vessel. In some embodiments, thesolvent flows through the extraction system without a pump. In anembodiment, the step of filling the solvent vessel further comprisesevacuating the solvent vessel to a substantial vacuum, for example apressure less than or equal to −25 inches of Mercury, −27 inches ofMercury, −29 inches of Mercury, or optionally, −29.5 inches of Mercury.In an embodiment, for example, the step of evaporating the solventreturns greater than 90%, greater than 95%, or optionally greater than99% of the solvent to the solvent vessel.

In an embodiment, the method for closed loop extraction of oils fromplant material further comprises providing a recovery pump operationallyconnected the collection vessel to force gas from the collection vesselto the solvent vessel. In an embodiment, the method for closed loopextraction of oils from plant material further comprises: (i) providinga source of inert gas in fluid communication with the solvent vessel;and (ii) flowing the inert gas into the solvent vessel while the solventis in the extraction vessel to promote the flow of the solvent into thecollection vessel. In an embodiment, the inert gas is argon, nitrogen ora combination thereof.

In some embodiments the present invention provides a means for thepurification of the extracted oils by the precipitation and removal ofimpurities such as waxes. Advantageously, the removal of these unwantedcompounds increases the potency of the extracted oils as some unwantedcompounds may interfere with the absorption or recognition of thedesired oil compounds, for example, increasing the pharmacologicalactivity associated with THC or increasing the intensity of fragrance ortaste provided by the oils in perfumes or food products, respectively.

In an embodiment, the method for closed loop extraction of oils fromplant material of claim 1 further comprises: (i) cooling the collectionvessel, thereby solidifying waxes in the at least a portion of the oils;(ii) coupling the collection vessel to a dewaxing vessel, wherein thedewaxing vessel is at a lower temperature than the collection vessel;and (iii) flowing the at least a portion of the oils from the collectionvessel to the dewaxing vessel through a filter, thereby removing thesolidified waxes. In an embodiment, for example, the filter is a 45micron or smaller filter, a sock filter, a 4-micron stainless steelfilter, or a combination thereof.

In embodiments, for example, the step of flowing the solvent from thesolvent vessel to the extraction vessel is accomplished by heating thesolvent vessel to between 20° C. and 40° C., greater than 40° C., andoptionally 25° C. and 35° C. and cooling the collection vessel to atemperature below 0° C., −5° C., −10° C., or optionally, −20° C. therebygenerating a pressure differential. In embodiments, the step of heatingthe collection vessel to evaporate the solvent heats the collectionvessel to between 20° C. and 40° C., greater than 40° C., or optionally,greater than 50° C. In an embodiment, the step of heating the collectionvessel the collection vessel is heated for between 40 and 80 minutes,greater than 60 minutes, or optionally, greater than 90 minutes. In someembodiments, the step of cooling the collection vessel to solidify waxescools the collection to less than 0° C., −5° C., −10° C., or optionally,−20° C.

In embodiments, the solvent is an alkane, an alkene, an alkyne or acombination thereof. In an embodiment, the solvent is natural gas. Insome embodiments, the solvent is ethane, ethene, propane, propene,butane, butene, pentane, pentene or a combination thereof. In anembodiment, for example, the solvent is n-butane.

In an aspect, provided is a method for closed loop extracting andpurifying oils and from plant material comprising the steps of: (i)providing an extraction system comprising: (a) a solvent vessel forcontaining a solvent; (b) an extraction vessel removably connected tothe solvent vessel; (c) a collection vessel removably connected to theextraction vessel and removably connected to the solvent vessel, whereinthe collection vessel is positioned gravitationally lower than theextraction vessel; (d) a dewaxing vessel removably connected to thecollection vessel; and (e) a filter, positioned in between thecollection vessel and the dewaxing vessel; (ii) evacuating the solventvessel to a pressure less than or equal to −25 inches of mercury; (iii)filling the solvent vessel with the solvent; (iv) heating the solventvessel, thereby flowing the solvent from the solvent vessel into theextraction vessel, wherein the solvent extracts oils from the plantmaterial; (v) heating the extraction vessel; (vi) cooling the collectionvessel to a temperature lower than a temperature of the solvent vessel,thereby flowing the solvent and oils into the collection vessel; (vii)heating the collection vessel to evaporate the solvent thereby returningat least a portion of the solvent to the solvent vessel and leaving atleast a portion of the oils in the collection vessel; (viii) cooling thecollection vessel to less than 0° C. thereby solidifying waxes in theoils; and (ix) cooling the dewaxed vessel to a temperature equal to orlower than the collection vessel, thereby flowing the oils from thecollection vessel through the filter to the dewaxed vessel and removingwaxes from the oils.

In an aspect, provided is a closed loop extraction system for extractingoils from plant material; the system comprising: (i) a solvent; (ii) asolvent vessel; (iii) an extraction vessel for housing a plant material,the extraction vessel removably connected to the solvent vessel; and(iv) a collection vessel positioned vertically below the extractionvessel and removably connected to the extraction vessel and the solventvessel; wherein the solvent flows from the solvent vessel to theextraction vessel containing the plant material thereby extracting oilsfrom the plant material; wherein the solvent flows from the extractionvessel to the collection vessel and the solvent is converted to a vapor,separating the solvent from the oils, and the solvent flows from thecollection vessel to the solvent vessel thereby completing a closedloop; and wherein the solvent flows by a pressure differential generatedby temperature difference between two connected vessels, bygravitational force or by a combination thereof.

In an embodiment, for example, the closed loop extraction system furthercomprises: (i) a dewaxing vessel removably connected to the collectionvessel; and (ii) a filter; wherein the oils are cooled to below 0° C.thereby separating waxes from the oils and flowing the oils from thecollection vessel through the filter to the dewaxing vessel, therebyremoving the waxes from the oils. In embodiments, at least one of thesolvent vessel, the extraction vessel or the collection vessel comprisesa liquid sight level. In embodiments, at least one of the solventvessel, the extraction vessel or the collection vessel comprises apressure relief valve.

In some embodiments, for example, first a solvent vessel is evacuated toremove any contaminants and is then filled with a solvent. The solventvessel is then heated to partially volatize the solvent and generatepressure within the vessel. The solvent vessel is then fluidicallyconnected to an extraction vessel containing plant material and thevaporized solvent, driven by a pressure differential, flows into theextraction vessel. Inside the extraction vessel, the solvent interactswith the plant material and extracts oils from the plant material intothe solvent. The extraction vessel is cooled or allowed to cool and thesolvent is allowed to at least partially condense into a liquid. Acollection vessel positioned gravitationally lower than the extractionvessel and is then fluidically connected to the extraction vessel Thesolvent, now containing oils from the plant material, flows from theextraction vessel to the collection vessel via gravity, a pressuredifferential (for example, caused by temperature difference) or both. Insome embodiments, a filter is placed between the extraction andcollection vessels to remove solids, for example loose plant mater. Thecollection vessel is then fluidically connected to the solvent vessel.Once inside the collection vessel, the oil/solvent mixture is heated andthe solvent at least partially vaporizes and is allowed to flow backinto the solvent vessel completing a closed loop. Thus, the remainingliquid in the collection vessel is predominately oils extracted from theplant material.

In some embodiments, the oil is next cooled, causing a precipitation ofcomponents with higher freezing temperatures, such as waxes. The cooledoil and precipitates then flow through a filter, removing the solidprecipitates, and into a dewaxing vessel. Thus, the final oil in thedewaxing vessel is dewaxed, i.e., has higher purity and has at least aportion of the waxes removed.

Without wishing to be bound by any particular theory, there may bediscussion herein of beliefs or understandings of underlying principlesrelating to the devices and methods disclosed herein. It is recognizedthat regardless of the ultimate correctness of any mechanisticexplanation or hypothesis, an embodiment of the invention cannonetheless be operative and useful.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides a flow diagram of an embodiment of a system for closedloop extraction of oils from plant material.

FIG. 2 provides a flow diagram of a method for closed loop extraction ofoils from plant material.

FIG. 3 provides an elevation view of an embodiment of a solvent vessel,an extraction vessel and a collection vessel supported by a frame andarranged to allow gravity to assist in flowing solvent from theextraction vessel to the collection vessel.

FIG. 4 provides an elevation view of a solvent vessel.

FIG. 5A provides a top view of a solvent vessel. FIG. 5B. Provides abottom view of the solvent vessel with a cut-away illustrating a diptube coupled to the liquid output port of the solvent vessel.

FIG. 6 is an elevation view of an extraction vessel.

FIG. 7 is an elevation view of a collection vessel.

FIG. 8 provides an embodiment of an extraction system including anoptional recovery pump coupled between the collection vessel and thesolvent vessel.

FIG. 9 provides an embodiment of an extraction system including anoptional inert gas tank coupled to the solvent vessel provided tofacilitate the flow of solvent from the solvent vessel to the extractionvessel.

FIG. 10 provides an elevation view of collection vessel coupled to adewaxing vessel.

FIG. 11A is an elevation view of a dewax filter. FIG. 11B is a crosssectional view of the filter provided in FIG. 11A taken through cutlines A-A.

DETAILED DESCRIPTION OF THE INVENTION

In general the terms and phrases used herein have their art-recognizedmeaning, which can be found by reference to standard texts, journalreferences and contexts known to those skilled in the art. The followingdefinitions are provided to clarify their specific use in the context ofthe invention.

“Closed loop” refers to a system which is configured as to not allowmaterial transfer between the system and the external environment and inwhich a flowing fluid is returned to it point or phase of origination.In an embodiment, for example, the system and methods are closed loopwith regards to a solvent. In some embodiments, the systems and methodsare not closed loop with respect to the plant material and/or extractedoils. In some embodiments, for example, a solvent is provided in asolvent vessel in the liquid phase and is converted to a gas or fluidphase and transported through the system eventually returning to thesolvent vessel, and in some embodiments, condensed back into the liquidphase. In some embodiments, closed refers to excluding material fromentering the system during operation, but material may leave the systemin certain circumstances such as pressure relief. In some embodiments,more than 80% of the solvent is retained and returned to the solventvessel for later use. In some embodiments, for example, more than 90%,more than 95%, or optionally, more than 99% of the solvent is retainedand returned to the solvent vessel for later use.

“Removably connected” refers to a configuration in which two or morevessels are placed in temporary communication with each other as to passmaterial, energy, electricity, data or a combination thereof betweeneach other. In some embodiments, removably connected refers toconnecting two vessels via a hose to allow fluid communication andmaterial transport between each other. In some embodiment, a hose isused to connect two quick connect valves of two vessels.

“Gravitationally Lower” refers to a physical position in which gravityforce directs matter from a higher position. In some embodiments,gravity facilitates the flow of a liquid to a gravitationally lowerposition. In an embodiment, gravitationally lower refers to positioninga vessel below another vessel so that gravity facilitates the flow of afluid to the gravitationally lower vessel, for example, between theextraction vessel and collection vessel in the provided systems andmethods.

“Plant matter” and “plant material” are used synonymously to refer toany material that is substantially composed of organic material fromplants. In some embodiments, plant matter refers to any materialcontaining essential oils and described herein. In some embodiments,plant matter refers to flowers, leaves, herbs, buds, stems or acombination thereof. In some embodiments, for example, plant mattercomprises cannabis, or for example, cannabis sativa, cannabis indica orcannabis hemp.

“Essential Oils” and “Oils” are used synonymously to refer to oilsextracted from plant material as described herein. In some embodiments,for example, oils refers to hydrophobic liquids containing aromatic orvolatile compounds. In some embodiments, oils refers to compoundsextracted from cannabis species, for example, tetrahydrocannabinol (THC)including Δ9-THC and Δ8-THC, Δ9-tetrahydrocannabinol propyl analogue,cannabidiol (CBD), cannabidiol propyl analogue, cannabinol,cannabichromene, cannabichromene propyl analogue and cannabigerol.

“Substantial Vacuum” refers to the sufficient absence of internalpressure to enable operability of a provided system or method, forexample, to enable flow between a pressured vessel and a vessel undersubstantial vacuum. In some embodiments, for example, substantial vacuumrefers to less than −25 in Hg, −27 in Hg, −29 in Hg, or optionally,−29.5 in Hg. In some embodiments, provided pressure measurements referto a gauge pressure, i.e., the amount of pressure that would appear on apressure measuring sensor which may vary with differences in atmosphericpressure. In some embodiments, for example, provided pressuremeasurements refer to absolute pressure corresponding to the actualpressure within the vessel.

As used herein, the terms “alkene” and “alkene group” are usedsynonymously and refer to a compound or functional group including acarbon-carbon double bond. Compounds of the invention may havesubstituted and/or unsubstituted C₁-C₂₀ alkenes, C₁-C₁₀ alkenes andC₁-C₅ alkene groups.

As used herein, the terms “alkyne” and “alkyne group” are usedsynonymously and refer to a compound or functional group including acarbon-carbon triple bond. Compounds of the invention may havesubstituted and/or unsubstituted C₁-C₂₀ alkynes, C₁-C₁₀ alkynes andC₁-C₅ alkyne groups.

The invention is further detailed in the following Examples, which areoffered by way of illustration and are not intended to limit the scopeof the invention in any manner.

EXAMPLE 1 Closed Loop Solvent Extraction

FIG. 1 depicts a schematic diagram showing an embodiment of a closedcircuit extraction system and FIG. 2 shows a method applied to theschematic. A predetermined amount of liquid solvent is placed within apreviously evacuated solvent vessel 110. Any type of liquid solvent thatis appropriate for the source material and desired extracts may beutilized. In an embodiment, for example, n-butane is utilized as asolvent for its relatively low cost, general availability, easy liquidand gas phase control, and ability to preserve the desired taste andaroma components (such as terpenes) that are extracted from substancessuch as cannabis. The source material placed within the extractionvessel 120 (see also FIG. 2, step 15) and is preferentially a groundplant material and may comprise plant matter such as cannabis sativa orhemp. After the source material is placed within the extraction vessel,the solvent vessel 110, extraction vessel 120 and collection vessel 130are coupled together (FIG. 2, step 25) as shown in the schematic of FIG.1 with the filter 125 interposed between the extraction vessel 120 andthe collection vessel 130. The liquid solvent is then transferred 115(FIG. 2, step 30) to the extraction vessel 120, where the liquid solventcomes in contact with the source material. The liquid solvent is allowedto remain in contact with the source material in the extraction vessel120 for some predetermined period of time, as explained below. After thedesired exposure time elapses, the liquid solvent along with the soluteextract is transferred through filter 125 into a collection vessel 130(FIG. 2, step 35). In one embodiment, the solvent is evaporated andtransferred 135 (FIG. 2, step 45) to the solvent vessel 110 usingtemperature and pressure differentials to transfer the gaseous solventto the solvent vessel 110. Chilling the solvent vessel 110 allows thesolvent to condense inside and complete a closed loop through the systemand leaving behind the extract within the collection vessel. This modeis called a passive mode of extraction, as no direct pumping is requirednor are any external inputs required other than temperature changes tocomponents of the system as described below.

In an embodiment of FIG. 1, a dewaxing configuration may be additionallyutilized (see FIG. 2, step 40) to further purify the extract taken fromthe source material. In one embodiment, the collection vessel 130 ischilled to a very low temperature, for example, below 0° C. This allowswax and other substances to precipitate into solids that can be filteredout from the oil in a separate filtration stage 140. The dewaxedcollection vessel 145 is coupled to the solvent vessel 110 and gaseoussolvent is transferred 150 and condensed within the solvent vessel 110.A purified and dewaxed extract may then be removed from the dewaxedextract collection vessel 145.

An additional embodiment is shown in FIG. 1, wherein an optionalrecovery pump 155 is coupled between either the collection vessel 130,or the dewaxed collection vessel 145 and back to the solvent vessel 110.This provides a mechanical assist to speed the transfer of the solventfrom either collection vessel 130 or 145 to the solvent vessel 110.

FIG. 3 shows an embodiment of a physical unit implementing part of theschematic illustrated in FIG. 1. Frame members 210 secure together thesolvent vessel 110 extraction vessel 120 and collection vessel 130 withthe collection vessel 130 positioned gravitationally lower than theextraction vessel 120, allowing gravity to assist with transfers of thesolvents and solutes from the extraction vessel 120 to the collectionvessel 130. A solvent transfer hose 211 is operably positioned betweensolvent vessel 110 and extraction vessel 120. A filter element 125 isinterposed between the extraction vessel 120 and the collection vessel130, and the flow solvent and solute along with pressure between vessels120 and 130 may be regulated through the collection valve 127 (alsocalled the main ball valve). Each of the major components of the systemis discussed in more detail below.

An embodiment of a solvent vessel is shown as an elevation view in FIG.4, with a cutout at the bottom area 110 h showing an internal view withthe stainless steel dip tube that approaches the proximity of the bottomof the solvent vessel 110. The solvent vessel 110 has a removable topsurface, a solvent hose quick connect 110 a where liquid solvent istransferred from the solvent vessel 110 to the extraction vessel. Thetop of the solvent vessel 110 is equipped with a pressure gauge 110 g,and a pressure release 110 b to meet safety regulations and to assistwith depressurization of the solvent vessel 110 after completion of theextraction process. The solvent vessel 110 is also equipped with one ormore sight glasses shown 110 d. 110 c and 110 f make it possible for theinterior of the solvent vessel to be accessed and cleaned.

FIG. 5A illustrates a top view of the solvent vessel 110. Also shown onFIG. 5A is a nitrogen intake quick release coupling 110 n to allow anoptional inert gas pressurization of the solvent vessel by acceptingpressurized inert gas above the headspace of the liquid solventcontained within the solvent vessel 110. As shown in FIG. 5B, a dip tube110 e is coupled with the solvent hose liquid access port or quickconnect 110 a, and through its proximity to the bottom of the solventvessel, such as within the proximity of 0.1-25 inches, liquid solvent isdrawn from the bottom of the solvent vessel 110 through the dip tube 110e, even as gaseous solvent or pressurized inert gas fills the headspaceabove the liquid solvent.

FIG. 6 depicts an elevation view of an extraction vessel 120. The top ofthe vessel 120 shows a ball valve and Quick Connect B 120 a that acts asa controllable port for the liquid solvent to enter the extractionvessel. The extraction vessel is equipped with a pressure relief 120 bto allow controlled release of excess interior pressures. The extractionvessel also allows access to the interior of the container through theremoval of clamps 120 c, 120 d, and 120 e. The internal access allowsplacing and removing source material, and cleaning of the extractionvessel 120 before or after its use.

FIG. 7 illustrates an elevation view of a collection vessel 130. Thisvessel is also similar to embodiments of the dewaxed extract collectionvessel 145 shown in FIG. 1. The collection vessel 130 has a collectionvalve 130 f, in some implementations a ball valve that allows selectiveaccess and pressurization of the collection vessel 130. Quick connect130 b allows solvent in a gaseous form to be removed from the collectionvessel 130 after the extraction process has occurred. Pressure gauge 130h is provided to allow for monitoring of internal pressures inconformance with process described herein. Pressure relief 130 g allowscontrolled release of interior pressure of the collection vessel 130 andremoval of the clamps 130 a or 130 e to allow access to the extractsdeposited inside.

FIG. 8 shows an embodiment of an extraction system that utilizes arecovery pump 155 to assist in solvent recovery. Recovery pump 155 iscoupled between the quick release 130 b of the collection vessel 130through collection hose 710, and to the gas input port quick release 110k of the solvent vessel 110 through hose 720. The arrows shown in thediagram illustrate the closed loop flow of solvent through the system,and after the extraction process is completed, extracts will remain inthe bottom of collection vessel 130, and solvent will be recovered tosolvent vessel 110. Although the passive mode described above works toperform the closed loop extraction, recovery pump 155 may serve to speedup or enable the recovery process.

FIG. 9 illustrates an embodiment of an extraction system in which aninert gas is provided into the solvent vessel to drive solvent into theextraction vessel. A gas cylinder 820, containing an inert gas, forexample nitrogen, is coupled through hose 810 to an inert gas input 110n, of the solvent vessel 110. The inert gas input 110 n enters the topspace of the solvent vessel 110 above the solvent contained in thevessel, thus adding pressure to the headspace above the liquid solvent.This additional pressure helps convey the solvent through the hose 211to the extraction vessel 120. The additional pressurization boostprovided by the inert gas optionally may be utilized to speed theextraction process as further described herein.

FIG. 10 illustrates a stacked combination of components utilized in anembodiment including a dewaxing step. The source vessel 130 has beenshown as removed from the previous configurations, inverted, and placedin communication with valve 140 D, which in some embodiments maycomprise a ball valve. A dewaxing filter 140 is coupled and interposedbetween the valve 140 D and valve 145 F, so as to capture and filter outprecipitates that have occurred as a result of chilling the collectionvessel 130 to a low temperature. The dewaxed collection vessel 145 thusreceives a highly purified form of the extract without any undesirablewaxy or precipitate substances, which have been removed.

FIGS. 11A and 11B illustrate embodiments of the dewax filter 140. FIG.11A is an elevation view showing the valve 140 d pressure relief 140 band sight glasses 140 c. A cut line A-A shown bisecting the dewax filter140 as illustrated in the cutaway view in FIG. 11B. In FIG. 11B, thesock filter 140 e as attached to the gasket is shown in an interiorvolume of the dewax filter 140. The clamps shown on the dewax filterallow internal access to change and or clean the dewax filter elements140 e.

EXAMPLE 2 Passive Closed Loop Solvent Extraction

In terms of a general process discussion the following is an embodimentof a process of the present invention to configure and use the system toobtain extracts from source material such as cannabis. The flowchartshown in FIG. 2 along with this schematic in FIG. 1 and the physicaldiagram FIG. 3 are useful in following the process in view of theparticular drawings shown in FIGS. 4-11B.

The initial step in the process begins by a purging/evacuation and fillstep for the solvent vessel. This is accomplished by attaching a vacuumpump to Quick Disconnect B (110 k) to pull a substantial vacuum (−25 to−29 HG) on the empty solvent vessel 110 to ensure full evacuation ofair.

While pulling a vacuum, the solvent vessel should be cooled to ensure aquick and smooth transfer of the liquid solvent. This will also increasethe level of the vacuum and promote the transfer of the solvent into thecontainer.

Once a substantial vacuum has been achieved, the solvent vessel 110 isplaced on a refrigerant recovery scale and the empty weight of thevessel is recorded for future reference.

After an empty container weight has been established, a solvent transferhose such as hose 211 is attached from a source solvent cylinder toQuick Disconnect B on solvent vessel 110. With empty container onrefrigerant scale, a tare button is pressed. Valve (110 k) attached toQuick Disconnect B and open solvent source valve are opened. Transfer ofsolvent may now begin. The Solvent vessel 110 is filled to the desiredweight. The liquid solvent transfer is monitored through the scale andliquid level sight glasses 110 d on the front of the solvent vessel 110.

Once desired solvent weight/level is achieved, solvent transfer isstopped by shutting off source valve first to ensure not to fill andpressurize solvent transfer hose. The solvent vessel 110 is placed inthe bucket to hold heating or chilling water and secured to the stand.

Assembly of an embodiment of the present invention may be undertaken asfollows, but dimensions mentioned are only exemplary and may compriselarger or smaller dimensions as desired. Place 8½″ Segment of 6″ Tubew/sight glass on 6″ Base Plate with 6″ n-Buna gasket placed in betweenensuring a proper seal. Affix 6″ SS Double Bolt Clamp and tighten clampbolts in an alternating pattern for even distribution of tension. Next,with another 6″ n-Buna gasket and 6″ Double Bolt Clamp, attach the 14½″segment of 6″ Tube w/sight glass. (Be sure to orient sight glasses in aconvenient position for observation.). Next with another 6″ n-Bunagasket and 6″ Double Bolt Clamp attach the 6″-2″ Conical Reducer to topof incomplete Collection Tube section.

Next using 2″ n-Buna gasket and 2″ Double Bolt Clamp, attach the “MainBall Valve w/2” fitting. With the completed collection vessel 130assembled, place it in the support stand and secure. It is recommendedto begin cooling the collection vessel 130 at this point.

Now with collection vessel assembled, an extraction vessel loaded withsource material (as described below) can be attached by attachinganother 2″ gasket and clamp set. Preparation of the extraction vessel120 is as follows.

Place desired extraction vessel on 4″-2″ Reducer Plate with 10.5 cmfilter paper sealed on top of 4″ n-Buna or nitrile gasket w/stainlesssteel screen in between to ensure proper filtration and an even seal onthe reducer. The filter paper is supported with SS screen below toprevent filter blow-outs. The filter is centered in the gasket toprevent damage to the seal.

After the filters and reducer are secured on the bottom the extractionvessel, the vessel is loaded with finely ground plant material. In oneconfiguration, 100-200 g of material such as finely ground cannabis isplaced into the tube of the extraction vessel and firmly but evenlypacked to ensure even distribution of solvent through the plantmaterial.

The interior of the column of the extraction vessel is filled up to somedistance (such as 2″) from the top of the extraction vessel, ensuringheadspace for dispersion ball on material tube caps, and allowing roomfor an even dispersion of solvent.

Loose plant material is removed from the seal on the extraction vesselwith a brush. Place extraction vessel cap (e.g. 4″ or 6″) oncorresponding sized extraction vessel (e.g. 4″ or 6″) with correspondingn-Buna gasket (e.g. 4″ or 6″) in between to ensure a complete and properseal. A corresponding Double Bolt Clamp (e.g. 4″ or 6″) should beaffixed and clamp bolts tightened to a desired torque in an alternatingpattern for even distribution of tension.

A filter element is coupled between the output of the extraction vesseland the collection valve as described elsewhere.

The solvent is then applied to the source material to obtain an extractfrom the source material through a passive extraction, a pump assistextraction, or a gas-assist extraction, or a combination thereof.

At this point, the collection vessel should be chilled with coupledextraction vessel to (−20° F. to 20° F.).

Passive closed loop extraction is performed using the aid of hot/coldtemperature differences and vacuum pressure to move and recover solvent.To begin this process, the collection vessel 130 should have beenchilled (−20° F. to 20° F.) with the extraction vessel 120 attached.

Likewise, the unit should be fully assembled and secured in the supportstand prior to operation. The Solvent Transfer Hose 210 should beconnected to Quick Disconnect B 120 a (FIG. 6) on top of the extractionvessel 120 and the ball valve 127 should be opened. A vacuum should bepulled on the collection vessel 130 and the extraction vessel 120 withthe hose assembly attached, to a gauge reading of at least −25 HG.

The Main Ball Valve 127 (FIG. 3) is closed below the extraction vessel120 (the lever should be horizontal). In some embodiments, the solventvessel 110 is placed in a warm water bath to build head space pressurethat will push the solvent into the next container (the extractionvessel 120). In embodiments, it is advised to not exceed 105° F. inwater bath or 50 psi in the solvent vessel 110 during this process. Theloose end of solvent transfer hose 211 should be attached to liquid portand Quick Disconnect A 110 a (see FIG. 5) on top of solvent vessel 110.The ball valve attached to Quick Disconnect A 110 a is opened to startflow of the solvent into the extraction vessel 120 begin the extraction.

In an embodiment, after 3-5 minutes have elapsed and solvent has hadtime to evenly fill the extraction vessel 120, the main ball valve 127is opened to allow liquid solvent to flow into the collection vessel130. Monitor the flow rate and color of the solvent/extract solution viathe collection vessel 130 sight glass 130L (see FIG. 7).

The liquid level sight glasses on the solvent vessel 110 and/or arefrigerant recovery scale is used to determine that the desired amountof solvent has left the solvent vessel 110. If some solvent stillremains, the solvent vessel 110 may be placed in a warm bath to buildpressure and push out the last of the solvent.

Once the desired amount of solvent has been transferred/removed fromsolvent vessel 110 the valve attached to Quick Disconnect A (110 a) isclosed and the solvent transfer hose 211 is removed from QuickDisconnect A. The valve on top of extraction vessel 120 is closed andthe solvent transfer hose 211 is removed from the Quick Disconnect A.The solvent vessel 110 is placed in a cold bath to reduce the pressure.If the container is cooled to a low enough temperature a vacuum may beachieved.

After the solvent vessel 110 is disconnected, heat is applied to theextraction vessel 120 to help push remaining solvent down into the coldcollection vessel 130. This can be done with an approved electricheating blanket or towel soaked in hot water. In some embodiments, itmay be helpful to isolate the extraction vessel 120 (via Main Ball Valve127) to build pressure and give an extra push. Once the extractionvessel 120 maintains a temperature at or above room temperature andthere is no visible dripping into the collection vessel 130, the MainBall Valve 127 can be closed.

A discharge hose is attached to the top of the isolated extractionvessel 120 to relieve pressure. With the discharge hose still attachedthe Extraction vessel 120 is removed. Remove the Extraction vessel 120at the connection to the top of the large ball valve. This will keep the4″-2″ SS Reducer Plate and filter attached to the column to protectagainst a rapid discharge of plant material from the Extraction vessel120.

When the extraction vessel 120 has been removed, it can be disassembledand emptied. Note that the spent plant material may still have somesolvent soaked in it and should be unpacked in a well-ventilated area,promptly removed and safely disposed of.

Once the Extraction vessel 120 is removed recovery can begin byattaching the Solvent Transfer Hose to Quick Disconnect on the ConicalSection of the Collection vessel 130, attach the other end of theSolvent Transfer Hose to Quick Disconnect B on the top of the Solventvessel 110. The bath surrounding the Collection vessel 130 can now bewarmed allowing the solvent to evaporate easier; the Solvent vessel 110should already be cooling. Open Quick Disconnect B on the top of theSolvent vessel 110 allowing transfer of solvent vapor from Collectionvessel 130 to Solvent vessel 110.

In some embodiments, recovery of solvent can take anywhere from 40minutes to an hour and 15 minutes. Be sure to replace the water in thebath as it cools. In some embodiments, the temperature of the bathshould not exceed 105° F.

Once the Collection vessel 130 has hit less than 10 psi at 80° F. therecovery can be stopped. (If desired, recovery can continue until thecollection vessel 130 reaches vacuum). Disconnect the solvent transferhose from the Quick Disconnect B on the conical section of thecollection vessel 130. Close the valve attached to Quick Disconnect B onthe solvent vessel 110 and disconnect the solvent transfer hose. Afterthe collection vessel 130 has been isolated and is holding at less than10 psi at 80° F. it is safe to depressurize, preferably slowly. When allpressure is relieved it is safe to open up the collection vessel 130 andretrieve the extract from the bottom. Do this by attaching a dischargehose line to collection vessel 130 to let pressure equalize, then openthe main ball valve before unbolting clamp on collection vessel 130.

EXAMPLE 3 Recovery Pump Assisted Closed Loop Solvent Extraction

Certain embodiments may achieve improved performance through use ofmechanical assistance to aid in speed and recovery of the solvent. Amechanical recovery pump utilizes a vacuum and pressure to pull solventvapor from a collection vessel and move it to a solvent vessel where itis condensed back into a liquid. Note that if a flammable or explosivesolvent is being utilized, the recovery pump 155 must be explosion proofand designed for hydrocarbon use.

The solvent transfer hose 211 should be connected to the QuickDisconnect B 120 a on top of the extraction vessel 120 (see FIG. 6),open corresponding ball valve at 120 a. Attaching the hose now ensuresthat a vacuum is pulled on the hose aiding further in solvent transfer.

Attach one end of Solvent Transfer Hose to the IN port on the recoverypump (not supplied) and attach the other end of the hose to the QuickDisconnect on the conical section of the Collection vessel 130. Pullcollection vessel 130 and Extraction vessel 120 assembly to a vacuum ofat least −25 to 29 HG. The Collection vessel 130 should be chilled (forexample −20° F. to 30° F.) with extraction vessel 120 attached. Pull avacuum in the entire unit. At this point, the solvent vessel 110 isplaced in a cold bath (for example −20° F. to 30° F.). Close the mainvalve 127, below extraction vessel 120.

Attach loose end of solvent transfer hose 210 to Quick Disconnect A (see110 a on FIG. 4) on top of solvent vessel 110. Attach one end of a thirdsolvent transfer hose to the out port on the recovery pump; attach theother end to Quick Disconnect B (see FIG. 4, 110 a) on the solventvessel 110. Start the recovery pump and open the ball valve attached toQuick Disconnect A. Also open ball valve attached to Quick Disconnect B.The valve on the top of the Extraction vessel 120 should already beopen. The extraction cycle has now begun.

Monitor the flow rate and color of the solvent/extract solution. Afterdesired results have been achieved close the ball valve attached toQuick Disconnect A stopping the flow of fluid. The recovery cycle hasnow begun. The recovery pump will now slowly reduce the pressure in thecollection vessel 130 and extraction vessel 120 assembly. When thepressure reaches less than 10 psi, close the main ball valve, isolatingthe extraction vessel 120.

Using a discharge line relieve the remaining pressure from the isolatedextraction vessel 120. With the discharge hose still attached begin toremove the Extraction vessel 120. Only remove the extraction vessel 120at the connection to the top of the main ball valve. This will keep the4″-2″ SS Reducer Plate and filter attached to the column to protectagainst a rapid discharge of plant material from the Extraction vessel120.

When the Extraction vessel 120 has been removed, the column can bedisassembled and emptied. Note that the spent plant material may stillhave some solvent soaked in, it should be unpacked in a well-ventilatedarea, promptly removed and safely disposed of.

After completing previous step, (extraction vessel 120 is unloaded)return to the collection vessel 130 to finish recovery.

Once the collection vessel 130 has hit less than 10 psi at 80° F. therecovery can be stopped. (If desired recovery can continue until thecollection vessel 130 reaches desired vacuum). Disconnect the solventtransfer hose 211 from the Quick Disconnect on the conical section ofthe collection vessel 130. Close the valve attached to Quick DisconnectB on the solvent vessel 110 and disconnect the second solvent transferhose.

After the collection vessel 130 has been isolated and is holding at lessthan 10 psi at 80° F., it is safe to depressurize slowly. When allpressure is relieved it is safe to open up the collection vessel 130 andretrieve the extract from the bottom. Do this by attaching a dischargehose line to collection vessel 130 to let pressure equalize, then openthe main ball valve before unbolting clamp on collection vessel 130.

EXAMPLE 4 Nitrogen Assisted Closed Loop Solvent Extraction

Nitrogen assisted operation utilizes pressure from an inert gas to pushsolvent through the extraction vessel 120. Using inert gas as a pressuresource allows the temperature of the solvent to be reduced. Beginningoperation the unit should already be assembled and secured in thesupport stand. Connect solvent transfer hose to Quick Disconnect A ontop of the Extraction vessel 120, open the corresponding ball valve.Pull vacuum on collection vessel 130 and extraction vessel 120 assembly.(Attaching the hose now ensures that a vacuum is pulled on the hoseaiding further in solvent transfer)

Be sure the collection vessel 130 is cool (to desired temperaturebetween −20° F. to 20° F.) with extraction vessel 120 attached. Pull theentire unit (excluding solvent tank) to at least −25 to 29 HG. Be surethat the solvent vessel 110 is in a cold bath (for example −20° F. to20° F.). Attach a hose from the nitrogen regulator to the Nitrogen Port(see FIG. 3) on the solvent vessel 110 and open valves. Fill the solventvessel 110 with 10-30 psi of nitrogen pressure. Close main ball valve127 below extraction vessel 120.

Attach loose end of Solvent Transfer Hose to Quick Disconnect A on topof Solvent vessel 110. Open ball valve attached to Quick Disconnect A tostart flow and begin the extraction. After 3-5 minutes have elapsed andsolvent has had time to evenly fill the extraction vessel 120, open thelarge ball valve to allow flow into the collection vessel 130. Monitorthe flow rate and color of the solvent/extract solution.

After a desired amount of flush time cut off nitrogen supply to Solventvessel 110 and close the valve attached to Quick Disconnect A, stoppingliquid flow. Close main ball valve 127 isolating the collection vessel130. To depressurize the collection vessel, use the discharge hose toQuick Connect to the conical section of the collection vessel todischarge nitrogen.

After reducing pressure re-open the large main ball valve allowingleftover solvent to flow into the collection vessel 130. Sometimes itmay be helpful to isolate the extraction vessel 120 to build pressureand give an extra push. Once the extraction vessel 120 maintains atemperature at or above room temperature and no there is no visibledripping into the collection vessel 130 the main ball valve can beclosed.

Attach a discharge hose to the top of the isolated extraction vessel 120to relieve pressure. With the discharge hose still attached begin toremove the extraction vessel 120. Only remove the extraction vessel 120at the connection to the top of the main ball valve 127. This will keepthe 4″-2″ SS Reducer Plate and filter attached to the tube to protectagainst a rapid discharge of plant material from the extraction vessel120.

When the extraction vessel 120 has been removed, it can be disassembledand emptied. Note that the spent plant material may still have somesolvent soaked in it and should be unpacked in a well-ventilated andpromptly removed and safely disposed of. The Nitrogen pressure willstill need to be relieved from collection vessel 130 with discharge hoseline before recovery may begin. Once the extraction vessel 120 isremoved recovery can begin by attaching the Solvent Transfer Hose toQuick Disconnect on the conical section of the collection vessel 130(see FIG. 5A), attach the other end of the solvent transfer hose 211 toQuick Disconnect B on the top of the solvent vessel 110.

The bath surrounding the collection vessel 130 can now be warmedallowing the solvent to evaporate; the solvent vessel 110 should alreadybe cooling. Open the ball valve on the top of the solvent vessel 110allowing transfer of solvent vapor from Collection vessel 130 to solventvessel 110. In some embodiments, recovery of solvent can take anywherefrom 40 minutes to an hour and 15 minutes. Be sure to replace the waterin the bath as it cools but the bath should not exceed 105° F. Once thecollection vessel 130 has hit less the 10 psi at 80° F. the recovery canbe stopped. (If desired recovery can continue until the collectionvessel 130 reaches and vacuum) Disconnect the Solvent Transfer Hose fromthe Quick Disconnect on the conical section of the collection vessel130. Close the valve on attached to Quick Disconnect B on the Solventvessel 110 and disconnect the solvent transfer hose 211.

After the collection vessel 130 has been isolated and is holding at lessthan 10 psi at 80° F. it is safe to depressurize slowly. When allpressure is relieved it is safe to open up the collection vessel andretrieve the extract from the bottom. Do this by attaching a dischargehose line to the Quick Connect of the collection vessel 130 to letpressure equalize, then open the main ball valve before unbolting clampon collection vessel 130.

EXAMPLE 5 Dewaxing Purification

Dewaxing, (or ‘Dwaxing’) in terms of extraction, is a technique toclarify oil produced with higher concentrations of undesirables, and away to increase the potency of the final product. In some embodiments,it means to cool the solvent solution with dissolved solute extracts fora given amount of time until waxes and other constituents begin to forma precipitate within the solution so they may be filtered out. Theseconstituents are physically and chemically different from the oil andare currently considered undesirable. After precipitation the undesiredcompounds are physically removed by filtration. The resulting product isnow considered “dewaxed”.

Embodiments of the present invention have the ability to dewax/winterizethe extraction product, with additional configuration from the baseunits shown in FIG. 1. In addition to collection vessel 130, a secondcollection vessel 145 of equal size to the other vessel 130 will beutilized (for example, sizes may include a 1 lb, 3 lb, or 5 lbcollection vessel 130), and an exemplary 8″×4″ Dewax filtration columnusing a 45 micron stainless steel Dewaxing filter, an 4″ double boltclamp, several extra N-buna gaskets.

Run the system as described above, but stop at the point where thesolvent/solute extract solution is fully contained inside the bottomcollection vessel 130.

After the extraction vessel 120 has been removed from the collectionvessel 130, the full collection vessel 130 can be removed from thestand. The reducer should be removed from the extraction vessel 120 tobe cleaned and replaced back on top of the main ball valve 127 on thecollection vessel 130 with a n-Buna gasket and double bolt clamp.

The full collection vessel 130 can then be cooled to a sub-zerotemperature using ice or dry ice, chiller or a spark/explosion proofrated freezer for a desired length of time, and the extraction productis now considered to be ‘dewaxing’.

While the product is dewaxing, assembly of the dewax filtration columnon top of your the second collection vessel 145 may be undertaken usingan n-Buna gasket and double bolt clamp.

The 45 micron stainless steel dewaxing filter should be placed into thetop of the dewax filtration column. Optionally, a snap-on cover orcellophane may be used to keep the filter free from debris. Close theball valve and use vacuum pump to achieve collection vessel 130 vacuumin order to reduce vacuum time.

Chill the second collection vessel 145 with the dewax filtration columnattached down to the same temperature or colder of the first collectionvessel 130, for example for two hours, before filtration to ensure evenchilled temperature throughout the steel. This will prevent the solventfrom warming up upon transfer, which could create vapor pressure andslow or stop the filtration process.

Once the dewax solution in the original collection vessel 130 has beenchilled for a desired period of time, remove the empty collection vessel130 (with dewax filtration column attached) from the freezer and secureit in position to receive solution. Remove the solution filledcollection vessel 130 from the freezer, rotate 180 degrees, and attachit to the top of the filtration column using a 4″ double bolt clamp. (Besure to remove plastic cover/cellophane wrap). After the solution filledcollection vessel 130 is attached to the top of the frozen emptycollection vessel 130, open the ball valve of the receiving lower/emptycontainer. This will expand the space of the current vacuum. Additionalvacuum reduction can then continue on the lower half of the system usingan HVAC pump. Time is of the essence during this stage because dewaxedmaterial can warm up while a vacuum is being pulled, but a vacuum cannotbe created on the filtration column until both collection vessels 130,145 are attached to isolate the system from the external environment.

Now that vacuum has been achieved in the lower collection vessel 145with the lower main ball valve open, the upper ball valve can be openedto release the solvent/oil/wax extract solution, allowing it to passthrough the dewax filter and collect in the bottom of the emptycollection vessel 145. If the user has access to an approved, explosionproof solvent recovery pump, the filtration process can be assisted byattaching the intake of the recovery pump to the quick connect on thelower collection vessel 130, and attaching the output of the recoverypump to your solvent vessel 110, using the vacuum to pull the solutionthrough the filter.

Now with the dewaxed solution completely transferred into the lowercollection vessel 145, close both main ball valves, isolating the 2collection vessels 130, 145 from one another. The user can now removethe upper collection vessel 130 and dewax filtration column for cleaningof wax and solids. Even after clamps have been removed, the vacuum onthe upper collection vessel 130 may be removed in order to remove thepieces on the unit, which can be done by depressing the male QuickConnect on the conical reducer or by attaching a pressure relief hose tothe Quick Connect. At this point solvent recovery may be undertaken asperformed above in relation to passive operation from the collectionvessel 145 as normal.

Changes and modifications may be made to the disclosed embodimentswithout departing from the scope of the present invention. These andother changes or modifications are intended to be included within thescope of the present invention, as expressed in the following claims.

STATEMENTS REGARDING INCORPORATION BY REFERENCE AND VARIATIONS

All references throughout this application, for example patent documentsincluding issued or granted patents or equivalents; patent applicationpublications; and non-patent literature documents or other sourcematerial; are hereby incorporated by reference herein in theirentireties, as though individually incorporated by reference, to theextent each reference is at least partially not inconsistent with thedisclosure in this application (for example, a reference that ispartially inconsistent is incorporated by reference except for thepartially inconsistent portion of the reference).

The terms and expressions which have been employed herein are used asterms of description and not of limitation, and there is no intention inthe use of such terms and expressions of excluding any equivalents ofthe features shown and described or portions thereof, but it isrecognized that various modifications are possible within the scope ofthe invention claimed. Thus, it should be understood that although thepresent invention has been specifically disclosed by preferredembodiments, exemplary embodiments and optional features, modificationand variation of the concepts herein disclosed may be resorted to bythose skilled in the art, and that such modifications and variations areconsidered to be within the scope of this invention as defined by theappended claims. The specific embodiments provided herein are examplesof useful embodiments of the present invention and it will be apparentto one skilled in the art that the present invention may be carried outusing a large number of variations of the devices, device components,and method steps set forth in the present description. As will beobvious to one of skill in the art, methods and devices useful for thepresent methods can include a large number of optional composition andprocessing elements and steps.

Whenever a range is given in the specification, for example, atemperature range, a time range, or a composition or concentrationrange, all intermediate ranges and subranges, as well as all individualvalues included in the ranges given are intended to be included in thedisclosure. It will be understood that any subranges or individualvalues in a range or subrange that are included in the descriptionherein can be excluded from the claims herein.

All patents and publications mentioned in the specification areindicative of the levels of skill of those skilled in the art to whichthe invention pertains. References cited herein are incorporated byreference herein in their entirety to indicate the state of the art asof their publication or filing date and it is intended that thisinformation can be employed herein, if needed, to exclude specificembodiments that are in the prior art. For example, when compositions ofmatter are claimed, it should be understood that compounds known andavailable in the art prior to Applicants invention, including compoundsfor which an enabling disclosure is provided in the references citedherein, are not intended to be included in the composition of matterclaims herein.

As used herein, “comprising” is synonymous with “including,”“containing,” or “characterized by,” and is inclusive or open-ended anddoes not exclude additional, unrecited elements or method steps. As usedherein, “consisting of” excludes any element, step, or ingredient notspecified in the claim element. As used herein, “consisting essentiallyof” does not exclude materials or steps that do not materially affectthe basic and novel characteristics of the claim. In each instanceherein any of the terms “comprising”, “consisting essentially of” and“consisting of” may be replaced with either of the other two terms. Theinvention illustratively described herein suitably may be practiced inthe absence of any element or elements, limitation or limitations whichis not specifically disclosed herein.

One of ordinary skill in the art will appreciate that startingmaterials, biological materials, reagents, synthetic methods,purification methods, analytical methods, assay methods, and biologicalmethods other than those specifically exemplified can be employed in thepractice of the invention without resort to undue experimentation. Allart-known functional equivalents, of any such materials and methods areintended to be included in this invention. The terms and expressionswhich have been employed are used as terms of description and not oflimitation, and there is no intention that in the use of such terms andexpressions of excluding any equivalents of the features shown anddescribed or portions thereof, but it is recognized that variousmodifications are possible within the scope of the invention claimed.Thus, it should be understood that although the present invention hasbeen specifically disclosed by preferred embodiments and optionalfeatures, modification and variation of the concepts herein disclosedmay be resorted to by those skilled in the art, and that suchmodifications and variations are considered to be within the scope ofthis invention as defined by the appended claims.

We claim:
 1. A closed loop extraction system for extracting oils fromplant material; said system comprising: a solvent; a solvent vesselhaving a top; an extraction vessel for housing a plant material, saidextraction vessel removably connected to said solvent vessel; acollection vessel positioned vertically below said extraction vessel andremovably connected to said extraction vessel and said solvent vessel; ameans for heating the solvent vessel; a means for cooling the extractionvessel; wherein said solvent flows from said solvent vessel to saidextraction vessel containing said plant material thereby extracting oilsfrom said plant material; wherein said solvent flows from saidextraction vessel to said collection vessel and said solvent isconverted to a vapor, separating said solvent from said oils, and saidsolvent flows from said collection vessel to said solvent vessel therebycompleting a closed loop; and wherein said solvent flows by a pressuredifferential generated by temperature difference between two connectedvessels, by gravitational force or by a combination thereof.
 2. Theclosed loop extraction system of claim 1 further comprising: a dewaxingvessel removably connected to said collection vessel; and a filter;wherein said oils are cooled to below 0° C. thereby separating waxesfrom said oils and flowing said oils from said collection vessel throughsaid filter to said dewaxing vessel, thereby removing said waxes fromsaid oils.
 3. The closed loop extraction system of claim 2, furthercomprising a first pressure gauge operatively connected to the top ofthe solvent vessel, a second pressure operatively connected to thecollection vessel, and a third pressure gauge operatively connected tothe dewaxing vessel.
 4. The closed loop extraction system of claim 1,wherein at least one of said solvent vessel, said extraction vessel orsaid collection vessel comprises a liquid sight level.
 5. The closedloop extraction system of claim 1, wherein at least one of said solventvessel, said extraction vessel or said collection vessel comprises apressure relief valve.
 6. The closed loop extraction system of claim 1,further comprising a recovery pump operatively connected to thecollection vessel.